Deutsche Bank gained a reputation during the financial crisis for deftly handling its numbers—a skill it clearly hasn't lost. The German bank glided through a potentially tricky profit warning this week by persuading investors that a big rise in costs was due to its conservative approach to charges from the three acquisitions in the past year. Meanwhile, it tantalised investors with the prospect of a record quarter for revenue. But all is not quite what it seems.

The record €7.4bn in revenue materialised on Thursday, but not quite as anticipated. Fixed-income sales and trading income, one of Deutsche's most important revenue sources, fell 40% quarter-to-quarter, after stripping out markups on toxic debt. That was well below expectations and one of the weakest performances among the major Wall Street players. This was partially offset by a strong performance in equities and corporate advisory, though these are smaller businesses. The bulk of the revenue increase relates to Postbank, acquired late last year.